My son has an 86 300e and the transmission will not shift gears. He says he hit a pot hole and now the problems started (I dont think it happened that fast).

As I test drove the car the tranny would only stay in low gear. Not sure if it was 1st or 2nd, but the tach was revving at about 5k doing 20 mph. I disconnected the kickdown switch behind the gas pedal and could get it to start in what appears to be 2nd and stay there. It would not upshift at 5k even.

Today we put some trans x in and now it will start in 2nd and not upshift from there. If I put the gear selector in 2 it appears to go to 1st gear when going slow and when I put gearshift to 3 it appears to go into 2nd gear also. It appears to me that the trans x has at least helped it this much.

It does not appear to be the selector being wrong as reverse is reverse and neutral is neutral and drive makes it go forward.

Before he has to cough up all the dough he has for a rebuilt tranny is there any other things I can check to make sure the tranny is bad? I have checked the fluid many times and it does not appear to be burned and the level is good.

Thanks for any and all information you guys may have.

check linkage motion , go under the car safely jacked up and with jackstands and check full range of motion of linkage while car is NOT running. report back on what you find

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Jerry

2004 SL500 Black 55K Miles
2002 s500 Black 90K Miles
1986 300E Gold 233K Miles
1966 Twin Cessna 320D
1989 Jeep Cherokee 233K Miles
1994 Ford Van E150 399K Miles

Thanks for the answer Jerry. I put the car up on ramps and checked a few things more. The Linkage appears to functioning properly with a full range of motion. Every position on the gear selector moves the gear selector on the transmission and all appears to have correct detents. Drove the car again and I still only have 1st and 2nd gears.

I unhooked the vacuum to the modulator from the manifold connection side and test drove vehicle again. Still only 1st and 2nd gear and the gears did not appear to slam when changing gears. In fact there did not appear to be any change in shift quality.

I hooked that back up and then unhooked the kickdown cable at the throttle linkage side, rendering the mechanical kickdown portion of the transmission inoperable. Test drove the car again and still only have 1st and 2nd gear. I cleaned the parts well and checked for full motion on the cable and hooked it back up, test driving the car again. Still only 1st and 2nd gear.

During all of these tests the electrical kickdown switch behind the gas pedal has been disconnected. I still have not reconnected this switch as I do not think that would have any affect or help in troubleshooting.

I also grilled my son about how it happened. Now he says he was going down the freeway at 70-75 (probably faster knowing him) and the car started shaking violently. He slowed down and the car would not go over 40 mph. He really has no idea how a car operates (a point of contention between his mother and I) so I am assuming the tach redlined and the shaking was misfiring. He still drove the car at 40 mph to get it home and for about a week before he told me of the troubles. He had been redlining the motor to try to get to speed for a week (I am very upset about that).

Anyway, that's the story as I know it and that is what i have done to check things out. Any other ideas as to what may be wrong so he does not have to find a different tranny?

Man, I hate to see when those rich kids at my school who drive really new MBs abuse them over potholes and speed in a school zone... terrible.....

I think that may be your B2 piston (on transmission) is not broken, but damaged... I read that if the B2 piston completely fails/shatters, you loose all FORWARD gears.... so may be your B2 piston is cracked or split???? Sorry, I am having a hard time figuring out how only 2 gears work....

You have ruled out you linkage... so it seems...
You have also ruled out your vaccum line ... so it seems....

Man, you really go me stumped... lemme see if my owner's bible addresses this issue in the trouble shooting...

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2006 BMW M5 "Heidi" @ 109,000 miles
2005 MBZ C55 AMG "Lorelai" @ 165,000 miles
1991 MBZ 300E "Benzachino II" @ 165,000 miles
1990 MBZ 500SL "Shoshanna" @ 118,000 miles

(On the hunt for a good used M103 engine as of 6/10/23, PM me if you have one to sell!)

I had 420sel I had problems with 2 trannys before I rebuilt one of them. In 1st tranny would slip in 2nd then it wouldnt go into 3rd and 4th. In 2nd it wouldnt go into4th. So I took 1st to rebuild. When I opened clutches drums all frictions plates were gone. So I replaced friction plates and all seals put transmission back in the car and it worked fine ever since. I think 300e and 420sel transmissions are the same. Im thinking to rebuild my 300e tranny since there is a slight slip in 3rd. Maybe if you never had any slippage in your transmission you have some of the valve body pistons bad. If youre mechanicaly enclined you can remove valve body with transmission on car. It can be removed when you remove transmission oil pan. I think you can buy valve body seals kit and replace seals but not sure about 300E. Its available for 420sel. Good luck

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1999 ML430 Silver 135k ml
Smoked LED taillights, Alpine in-dash DVD player, 12" sub, Pioneer components, 2 amps, 4200k HIDs, ML55 headlights, 20" rims, mirror LED blinkers

SOLD. 1996 E320 145k ml. Burgundy

SOLD but miss it everyday 1992 500sel Black
Chime buzzer mod,Alpine CD/MP3 player with stock amp,Euro headlights,S600 grill,20" rims, BEST CAR EVER!

SOLD. 1990 300E White
187k ml,smoked tails,Euro headlights,17rims,Intake,12" sub in first aid kit,alarm/autostart,buzzer mod

Well, tranny died on Saturday. The boy refused to quit driving it and he got stuck. Anybody looking for a good body '86 300e? It is gold with the tan interior, Motor still runs well, seats are a little tore up, tranny obviously shot and it has a hole in the muffler.

Thanks for all of your ideas and suggestions, but I think the boy is getting out of Mercedes for a few years.

Sorry to hear that the car gave up, I am sure you will find some one to buy it.

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2006 BMW M5 "Heidi" @ 109,000 miles
2005 MBZ C55 AMG "Lorelai" @ 165,000 miles
1991 MBZ 300E "Benzachino II" @ 165,000 miles
1990 MBZ 500SL "Shoshanna" @ 118,000 miles

(On the hunt for a good used M103 engine as of 6/10/23, PM me if you have one to sell!)

Just tell them a old lady drove it